1. Field of the Invention
The present invention is related to a valve or any other open and close apparatus and particularly to a position restoring apparatus for an open and close device.
2. Brief Description of the Related Art
In order to pursue fast speed and convenience, an open and close function of electrical actuation has been developed by the manufacturers for controlling ball valve, butterfly valve or other types of valves.
However, in case of the valves being required to shut urgently under a condition of emergency and happening to power failure or power off accidentally, how to close the valves immediately is a problem bothering the manufacturers and the users. Besides, sometimes, the users desire to operate the valves manually but it is not possible for them to enter the shop to operate open or close of the valves.
U.S. patent application Ser. No. 11/159,685 filed by the present inventor entitled “POSITION RETURN DEVICE FOR AN OPEN AND CLOSE APPARATUS” has been allowed. The feature of the prior art is in that a valve or any open and close apparatus can be returned to the original opening or closing state in case of power failure or power being off accidentally. However, when the valve or any open and close apparatus has to be changed to a state different from the original state before the power being on again, the prior art is incapable of dealing with the special need.